I've been using S2U2 for a little over a week now and it seems that every since I've installed it my battery life has dramatically improved.
For example I would normally be at about 20% power left by 6pm. Now I'm at about 70%-80% power left at 6pm! Normally at 12pm I have anywhere from 40%-60% left. Now I average about about 80%-100% left. I carry a charger with me everywhere I go, but now I don't see the need to anymore.
Also it seems as though the days of picking up a "warm" phone are over. Before if I leave my phone unused in my holder for several hours, I will find that it's warm and the radio has apparently turned on for who knows why and failed to turn off. Now every time I touch my phone, it's cool and the screen is off and where I left it.
Could it be random screen presses could be the culprit of the phone turning on and quickly draining the battery? Why didn't HTC for see this and port Keyguard to the HTC.
In either case, I'm loving S2U2 but it's a shame you have to download an app just to get what I call normal functionaliy.